What is The Universe?

Basically, everything. All matter, energy and space. Time too, I suppose. Even that which we haven't seen or measured yet.

The question is what IS the Universe, not what WAS it or what WILL it BE. So the answer is that the Universe IS the totality of all matter and energy everywhere as it exists NOW and involves cosmology. What it WAS and what it WILL BE are two additional questions. They DO involve time and have entirely different answers involving cosmogony.

"Now" is an interesting concept if you try an apply it across the cosmos.

speedfreak is right. NOW is an interesting concept when applied to the Universe as a whole. We do not see the Universe as it is now. Because of the finite speed of light, we see nothing as it now, not even the moon. We see the moon as it was about 1.3 seconds ago, the sun as it was 8.3 minutes ago, the planet Neptune as it was about four hours ago, the nearest star other than the sun as it was 4.3 years ago, the Andromeda galaxy as it was about 2.6 million years ago, and the edge of the observable Universe as it was about 13.7 billion years ago.

so whens tea time ?

Time is an illusion. Tea time doubly so.

42.

I can't believe nobody answered that yet.

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"Half of what I say is meaningless, but I say it so that the other half may reach you."

So, my 'now' and your 'now' can never be the same 'now'.
...Now I get it! Oops! I meant NOW I get it. No - NOW! Awww, forget it!

jokergirl, what is the question you feel nobody has answered yet? If it's "What is the Universe?", It seems to me that both schlaugh and I answered it. If you feel that something is missing, I urge you to explain why. Hopefully, one of us or someone else can supply whatever you sense te be lacking.

She wasn't saying that, she was saying she was surprised that no one had answered "42" yet.


You know, the meaning of life, the universe, and everything.

thanks, Drunk Vegan.

the clue's in the name....

so all matter and energy? is space/time a ''thing'' ? or do we just have ratio's between things?

i kinda agree with lee smolin... ie that question needs an answer..

damian 1727, you ask, "Is space/time a "thing?" The indefiniteness of the meaning of the word "thing" makes your question hard to understand. Everything is a "thing" in one sense or another. That the Universe is made up of all matter and energy is about the most that one can say in answer to the question of what the Universe is. As for a ratio between mass and energy, it's not clear to me that there is any answer to that question since special relativity reveals that both are forms of the same thing. I really don't believe that anything more can be said in answer to your question.

From Douglas Florian's book of space poems Comets, Stars, the Moon and Mars.

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im talking about background independent" theories -- ones where there is no framework of absolute time and space for particles to move against, but rather ones where space and time themselves are integral, evolving, changing parts of the cosmos, and in which there are no static things, only dynamic processes....

being as there can be no outside to the universe....

http://www.edge.org/3rd_culture/smol...n03_print.html

Call me kooky, but as I understand it, there MUST be something outside the universe, for the matter and energy in the universe to exist.

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by definition the universe is eveything so there can be no outside...

Then if energy/matter can neither be created or destroyed in our universe, then how come it is here at all?

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Wow, this is the most arrogant reply I have seen in a long time. Not only did you not get the reference to "42", but you think you answered the question. Correctly, even.

yes but we like him as he is as dry as dry and knows a thing or two.....

Then if energy/matter can neither be created or destroyed in our universe, then how come it is here at all?

as nothing is less stable than something?

and also i guess in the past universe ment everything now we have multiverses .bubble universes and all sorts....

i myself like the infinite inflation model as its mind numbing in its scope !!

Dumb Amateur Astronomer: this is the most arrogant reply I have seen in a long time. Not only did you not get the reference to "42", but you think you answered the question. Correctly, even.

dcl: I'm sorry that you found my reply arrogant. I also regret that I did not and still do not recognize the reference to "42", whatever that means. In fact, I must admit that I didn't even notice it when I submitted my comment. I suspect it refers to something in "A Hitchhiker's Guide to the Galaxyi", but, never having read that beyond something at the beginning about, as I recall, bulldozing of a house, I don't even know that much, so all I can do is congratulate you on your superior knowledge.

damian1727: if energy/matter can neither be created or destroyed in our universe, then how come it is here at all?

dcl: Science has no answer for that question. Science observed that the Universe is expanding, inferred that it was smaller in the past and, using what is known about the behavior of matter and energy, in effect ran the movie backward as far as knowledge would allow and sensibly stopped there to avoid uninformed speculation. That took it back to 10-43 sec, at which time the size of the eniverse appeared to be as close as can be imagined to that of a dimensionless point and at a temperature so high that no matter of any kind could exist, not even protons, neutrons, electrons, etc., so that what was to become matter had to all be in the form of energy at a temperature of at least trillions of kelvins, the only form of energy possible at such temperatures being electromagnetic with black-body spectrum, the temperature being too high for any of the other three basic forms of energy. No one knows enough about the nature of energy to be able to run the "movie" any further back into the past, in particular to say anything about where that energy came from in the first place.

I don't see your logic, could you explain?
From where I stand, you can squeeze the universe back together again in a Big crunch, to 'get back' usable energy for the next Big Bang, but that still doesn't explain where it comes from. And if one says it has always existed, well that's the same answer theologians have been using for thousands of years. And if it doesn't work for HIM, why should it work for things moderately more concrete?

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damian 1727: You asked, "Is space/time a 'thing'? or do we just have ratios between things?" i kinda agree with lee smolin... ie that question needs an answer.

dcl: Special relativity introduced the concept of spacetime, written as a single unhyphenated word. Spacetime is seen as a four-dimensional entity and is visualized in terms of four mutually perpendicular directions, three of which are spatial and the fourth temporal, that is, forward and backward directions in time. Collectively, I suppose the four of them could be regarded as a thing, but it's not a material thing that you can touch or see. A common application of the concept is a two-dimensional diagram that can be drawn on a sheet of paper. It's called a "spacetime diagram". It can also be called a "space/time diagram" if one wishes. People will understand you whichever form you use. Both names appear in books and technical articles. The horizontal coordinate is a spatial direction with left and right. The vertical coordinate is time, with past downward and future upward. Light is depicted as a pair of lines at 45-degree angles to the vertical and horizontal lines. A special version of this diagram used to illustrate the meaning of the Lorentz transformation in special relativity is called a Minkowski diagram.

I don't understand your reference to Lee Smolin. The only context in which I've encountered Lee Smolin is string theory, and I don't think that's what you're referring to.

It is not useful to make controversial statements without backing them up with arguments for why you think they are valid. In the present instance, the first sentence in your statement is highly controversial. You need to provide an argument for why you think it is valid.